The present embodiments relate to medical diagnostic ultrasound. In particular, flow estimation is provided for medical diagnostic ultrasound.
Quantitative and qualitative images of velocity, energy, or variance depict the flow hemodynamics. Images help immediate diagnosis and also provide a trackable-methodology for short-term and long-term monitoring.
For Doppler velocity or color flow velocity imaging, a velocity scale is set. If the scale is set to be overly inclusive, then the dynamic range and sensitivity is poor. If the scale is set to narrowly, then high velocity data may be aliased (e.g., a positive velocity may appear as a negative velocity). When imaging pulsing flow, such as associated with the circulatory system, the maximum velocity varies as a function of time. Setting the velocity scale may be difficult in light of this variance.
The velocity information is an axial measurement. The velocity towards and away from the transducer along the scan line is measured. Where the flow is at an angle or not parallel with the scan line, the axial velocity may not accurately represent the speed of flow at the location.
Aliasing and/or use of axial velocity may result in inaccurate quantification. For qualitative assessment, the flow hemodynamics may be poorly or less accurately represented. The repeatability of measurements or assessment may be difficult due to different settings of the scale or scan angle.